Light Wallet: Gather transactions from immutable files and store them in the database

[jpraynaud]

Why

In order to sign the Cardano transactions, we need to retrieve them from the immutable files and store them locally on the signer and aggregator nodes.

What

Implement the gathering of transactions from immutable files in a database store, with a cache mechanism that allows to incremental retrieval of transactions.

How

• Create a new sqlite store (for maintainability)
  • In the aggregator
  • In the signer
• Make these data accessible from the store (create by chunk/read transaction hash, immutable file number and block number)
  • In the aggregator
  • In the signer
• Select the way to gather transaction ids from immutable file:
  • By using the pallas-hardano (preferred, but we need to make sure that we can retrieve the transactions by immutable file) (see chunks)
  • By scanning the raw immutable files and detecting the blocks with pallas(and their transactions) as prototyped in the PoC (README and import function)
• Implement the associated SignableBuilder
  • In the aggregator
  • In the signer

Later

• Create common database provider for Cardano transactions?